This invention relates to heat exchangers and, more particularly, to heat exchangers of the finned type.
It is a primary object of the present invention to afford a novel heat exchanger and a novel method of making the same.
Another object is to afford a novel finned heat exchanger wherein the fins are formed by cutting or gouging the same from wall portions of the heat exchanger.
Another object of the present invention is to enable a novel heat exchanger to be afforded in a novel and expeditious manner, wherein secondary heat transfer surfaces may be formed by cutting or gouging them out of tubular stock, to afford fins having internal openings extending therethrough.
An object ancillary to the foregoing is to enable such heat exchangers to be afforded in a novel and expeditious manner with elongated openings through the fins thereof.
Heat exchangers embodying fins formed from the outer surface material of tubular members have been heretofore known in the art, being disclosed, for example, in Richard W. Kritzer U.S. Pat. No. 3,202,212 and Joseph M. O'Connor U.S. Pat. No. 3,692,105, wherein, in the aforementioned Kritzer patent, the fins are in the form of spines formed from outwardly projecting ribs on the tubular member; and, in the aforementioned O'Connor patent, the fins are formed by cutting or gouging them from such outwardly projecting ribs and the portion of the tubular member directly underlying the ribs, to thereby afford fins having elongated base portions projecting outwardly from the side wall of the tubular member, with spaced spines projecting outwardly from the outer longitudinal edges of the base portions.
Also, heat exchangers embodying perforated fins formed from the outer surface material of tubular members have been heretofore known in the art, being disclosed, for example, in the Stephen F. Pasternak application for U.S. Pat., Ser. No. 438,750, filed Feb. 1, 1974 now U.S. Pat. No. 3,886,639 granted June 3, 1975. In the aforementioned application, the fins are formed by cutting or gouging them from outer surface portions of a tubular member, which portions have openings extending therethrough longitudinally of the tubular member.
Heat exchangers of the type disclosed in the aforementioned Kritzer and O'Connor patents and in the aforementioned Pasternak application have proven to be very effective. However, it is an object of the present invention to afford improvements over heat exchangers of the type disclosed in the aforementioned patents and application.
Another object of the present invention is to afford a novel heat exchanger of the finned type, wherein the fins are constructed in a novel and expeditious manner.
One of the disadvantages heretofore encountered, from time to time, in finned heat exchangers of the type wherein the fins are cut or gouged from outer surface material of a tubular member has been that, when the tubular members have been driven through cutting or gouging machines by drive members which frictionally engaged the surfaces from which the fins are formed, the frictionally engaged surfaces were marked by the drive member, with the result that the surfaces of the finished fins bore such marks and were roughened thereby. Such roughened surfaces have been known to cause an increased pressure drop and a reduced air flow, as compared to smoothsurfaced fins, when air is passed between such fins transversely to the length of the tubular member. It is another important object of the present invention to enable such an increase in pressure drop to be prevented.
Another object of the present invention is to enable such roughened surfaces to be eliminated in a novel and expeditious manner.
A further object is to enable a tubular member to be driven in a novel, positive-drive manner through a machine in which the fins are cut or gouged from the outer surface material of the tubular member.
Also, the formation of longitudinally extending openings in tubular members, such as the openings through which cuts or gouges are made in following the method disclosed in the aforementioned Pasternak application, Ser. No. 438,750, now U.S. Pat. No. 3,886,639 granted June 3, 1975 causes certain difficulties or problems. For example, when the holes are formed in an extruding operation, the provision of the necessary pins in the extrusion dies causes problems, which, of course, are not insurmountable, but are substantial. It is another important object of the present invention to overcome such problems.
An object ancillary to the foregoing is to overcome such problems while yet affording a tubular member having openings in the outer surface material, and through which openings cuts may be made, when cutting or gouging the surface material, to thereby afford fins having perforations therethrough.
Another object of the present invention is to afford a novel tubular member having openings through which cuts may be made in the aforementioned manner, and wherein the openings are constituted and arranged in a novel and expeditious manner in the outer surface material of the tubular member.
Yet another object is to enable such openings to be formed in the outer surface material of a tubular member in a novel and expeditious manner.
A further object of the present invention is to enable longitudinal movement of a tubular member and the formation of openings in the outer surface material thereof to be simultaneously effected in a novel and expeditious manner.
Another object of the present invention is to afford a novel method of manufacturing an elongated tubular member having openings in the outer surface material thereof, wherein the tubular member is longitudinally moved simultaneously with the formation of the aforementioned openings.
An object ancillary to the foregoing is to enable the movement of the tubular member and the formation of the openings in the outer surface thereof to be accomplished in a novel and expeditious manner.
A further object of the present invention is to afford a novel heat exchanger which is practical and efficient in operation, and which may be readily and economically produced commercially.
Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show preferred embodiments of the present invention and the principles thereof and what we now consider to be the best mode in which we have contemplated applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.